In the past, there have been various forms of valve trains proposed for multi-valve engines. One example can be seen in my U.S. Pat. No. 5,347,964, issued on Sep. 20, 1994 and entitled "Valve Train For Internal Combustion Engines". In this patent, I disclose a four-valve, double-overhead camshaft valve train in which the axes of the valves for each cylinder diverge outwardly from and are non-parallel with respect to the axis of the cylinder. The valve mechanism has a finger follower for each camshaft lobe and valve and a contact pad between the cam and the finger follower to permit rocking movement so that the orientation of the finger follower and the axis of the valve remain at a fixed relationship.
Also, in my U.S. patent application Ser. No. 08/416,245 filed on Apr. 4, 1995, and entitled "Valve Train For Internal Combustion Engine", I disclose a valve train utilizing an inverted bucket tappet with a slide and spherical joint structure operatively disposed between the bucket and the end of the valve stem allowing the valves to be angulated with respect to each other and to the axis of the cylinder in both the transversal and horizontal planes of the engine.
Another example of a valve train that can be used in a multi-valve engine can be seen in my co-pending U.S. patent application Ser. No. 08/578,369, filed on Dec. 26, 1995 and entitled "Valve Train for an Internal Combustion Engine". The valve train mechanism disclosed in this patent application is based on the use of a cross member, which as seen in one embodiment of the invention takes the form of a guided "T" bridge, and which serves to directly actuate an inverted bucket tappet through a roller and groove connection without any side thrust on the valve stem. In alternate embodiments disclosed in this particular application, the cross member is designed so that it can be stable without having a pin to guide movement as provided in the "T" bridge.
In addition, U.S. Pat. No. 4,558,667, issued on Dec. 17, 1985 in the name of Inagaki et al. and entitled "Valve Driving Apparatus For An Internal Combustion Engine", discloses a valve driving apparatus incorporated in an internal combustion engine that has plural valve stems in a cylinder head that are aligned radially about the cylinder with the intersection of their longitudinal axes substantially coinciding with a center of curvature of an upper wall surface of the combustion chamber. The valve stems are arranged so as to be driven by at least one camshaft through subsidiary rocker arms which are in abutment with respective tips of the valve stems and respective rocker arms which are in abutment with the subsidiary rocker arms. The valve train is characterized in that a shaft for each of the subsidiary rocker arms is positioned on a plane crossing a longitudinal axis of the corresponding one of the valve stems at a right angle and existing in a range of up-and-down stroke of the head of the same valve stem.
Another patent disclosing a valve train for a multi-valve engine is the U.S. Pat. No. 4,617,881, issued on Oct. 21, 1986 in the name of Aoi et al., and entitled "Actuating Mechanism For Multiple Valve Internal Combustion Engine". In this instance, there are two embodiments of valve arrangements that permit the use of a plurality of valves for a given combustion chamber while operating all of the valves through a camshaft arrangement. Some of the valves are operated directly by the cam lobes and others are operated by rocker arms. In addition, an embodiment discloses a two rocker arm arrangement for operating certain valves.
A still further disclosure of a valve train for a multi-valve internal combustion engine can be seen in U.S. Pat. No. 4,686,945, issued on Aug. 18, 1987 in the name of Inagaki et al., and entitled "Valve Structure For An Internal Combustion Engine". This patent shows an engine employing multiple valves which are mutually inclined. The valve actuating assembly disclosed includes two camshafts with primary rocker arms being driven by the camshafts and, in turn, drive secondary rocker arms. The secondary rocker arms are pivotally mounted about common shafts and extend to the valves. The common shafts are located between the valves.